EASA AD No : 2011-0144 

EASA Form 110 Page 1/2 

EASA AIRWORTHINESS DIRECTIVE 

AD No.: 2011-0144 

Date: 26 July 2011 

Note: This Airworthiness Directive (AD) is issued by EASA, acting in accordance with 

Regulation (EC) No 216/2008 on behalf of the European Community, its Member States and 

of the European third countries that participate in the activities of EASA under Article 66 of 

that Regulation. 

This AD is issued in accordance with EC 1702/2003, Part 21A.3B. In accordance with EC 2042/2003 Annex I, Part M.A.301, the 

continuing airworthiness of an aircraft shall be ensured by accomplishing any applicable ADs. Consequently, no person may 

operate an aircraft to which an AD applies, except in accordance with the requirements of that AD unless otherwise specified by the 

Agency [EC 2042/2003 Annex I, Part M.A.303] or agreed with the Authority of the State of Registry [EC 216/2008, Article 14(4) 

exemption]. 

Type Approval Holder’s Name : 

EUROCOPTER 

Type/Model designation(s) : 

EC 155, SA 365 and AS 365 Helicopters 

TCDS Number: DGAC France No. 159 

Foreign AD: Not applicable 

Supersedure: None 

ATA 05 

ATA 64 

Time Limits and Maintenance checks – Tail Rotor Hub (TRH) – 

Inspection 

Tail Rotor - Tail Rotor Hub - Inspection / Replacement 

Manufacturer(s): Eurocopter (formerly Eurocopter France, Aerospatiale) 

Applicability: Eurocopter EC 155 B, EC 155 B1, SA 365 N1, AS 365 N2 and AS 365 N3 

helicopters, all serial numbers, if equipped with a rotor hub with Part number 

(P/N) 365A33351100, P/N 365A33351101 or P/N 365A33351102 installed on 

the 10-blade Tail Rotor Hub of the quiet fenestron tail rotor. 

Reason: Two cases of cracked 10-blade TRH were recently reported to Eurocopter. 

This condition, if not detected and corrected, could lead to a tail rotor jam, 

possibly resulting in reduced or loss of control of the helicopter. 

For the reason described above, and pending further investigations, this AD 

requires repetitive inspections of the 10-blade TRH, and depending of 

findings, the replacement of the 10-blade TRH. 

This AD is considered an interim measure and further AD actions are likely to 

follow.

Effective Date: 09 August 2011 

Required Action(s) 

and Compliance 

Time(s): 

Required as indicated, unless accomplished previously: 

(1) Within 55 flight hours (FH) after the effective date of this AD, accomplish 

a detailed visual inspection of the 10-blade TRH hub in accordance with 

the instructions of Eurocopter EC 155 Alert Service Bulletin (ASB) 
EASA AD No : 2011-0144 

EASA Form 110 Page 2/2 

05A021 Revision 1, or Eurocopter AS 365 ASB 05.00.60 Revision 1, as 

applicable to the helicopter version. 

 An inspection performed before the effective date of this AD in 

accordance with Eurocopter EC 155 ASB 05A021 or Eurocopter 

AS 365 ASB 05.00.60 at original issue is acceptable to comply with the 

requirements of this paragraph. 

(2) Thereafter, at intervals not to exceed 55 FH, repeat the inspection of the 

10-blade TRH, in accordance with the instructions of Eurocopter EC 155 

ASB 05A021 Revision 1 or Eurocopter AS 365 ASB 05.00.60 Revision 1, 

as applicable to the helicopter version. 

(3) If, during an inspection as required by paragraph (1) or (2) of this AD, 

any crack is found in the TRH, before next flight, replace the TRH with a 

serviceable part, in accordance with the instructions of Eurocopter 

EC 155 ASB 05A021 Revision 1 or Eurocopter AS 365 ASB 05.00.60 

Revision 1, as applicable to the helicopter version. 

A TRH replacement accomplished before the effective date of this AD in 

accordance with Eurocopter EC 155 ASB 05A021 or Eurocopter 

AS 365 ASB 05.00.60 at original issue is acceptable to comply with the 

requirements of this paragraph. 

(4) Replacement of a TRH hub as required by paragraph (3) of this AD does 

not constitute terminating action for the repetitive inspection 

requirements of paragraph (2) of this AD. 

Ref. Publications: Eurocopter EC 155 ASB 05A021 Revision 1 dated 20 July 2011; 

Eurocopter AS 365 ASB 05.00.60 Revision 1 dated 20 July 2011. 

The use of later approved revisions of these documents is acceptable for 

compliance with the requirements of this AD. 

Remarks : 1. If requested and appropriately substantiated, EASA can approve 

Alternative Methods of Compliance for this AD. 

2. The required actions and the risk allowance have granted the issuance of 

a Final AD with Request for Comments, postponing the public 

consultation process after publication. 

3. Enquiries regarding this AD should be referred to the Safety Information 

Section, Executive Directorate, EASA. E-mail ADs@easa.europa.eu. 

4. For any question concerning the technical content of the requirements in 

this AD, please contact: EUROCOPTER (STDI) - Aéroport de Marseille 

Provence 13725 Marignane Cedex, France. 

Telephone +33 (0) 4 42 85 97 97, Fax +33 (0) 4 42 85 99 66. 

E-mail: Directive.technical-support@eurocopter.com.